Answer this question truthfully
### Question: What causes Chronic fatigue syndrome?
### Response: The exact cause of chronic fatigue syndrome (CFS) is unknown.
Some theories suggest CFS may be due to:
Epstein-Barr virus or human herpes virus-6 (HHV-6); however, no specific virus has been identified as the cause Inflammation in the nervous system, because of a faulty immune system response
The following may also play a role in the development of CFS:
Age Previous illnesses Stress Genetics Environmental factors
CFS most commonly occurs in women ages 30 to 50.